Human Usher syndrome, the most frequent cause of deaf blindness, is characterized by congenital deafness, due to loss of sensory hair cells, and progressive retinal degeneration, due to retinitis pigmentosa. Twelve different chromosomal loci have been linked to Usher syndrome and nine of the genes have been identified to date. Identification of the missing Usher genes is crucial for diagnosis and patient counseling. The nine known genes encode a surprisingly broad range of different types of proteins. Although the roles of these proteins are poorly understood, recent studies suggest that they function together in a multimolecular complex. This project focuses on analysis of the two scaffold proteins that play a central role in organizing the complex, and a new potential member of this organizing scaffold. The project has three main aims: 1) to determine whether the newly discovered gene encodes an Usher scaffold protein, 2) to analyze the functions of the scaffold proteins in organizing the Usher proteins into a complex, and 3) to determine how the Usher protein complex functions in cells of the inner ear and retina.